Gut microbiome of obese cats differs from lean cats

Cats are notorious for excessive food intake and lazing around all day. When combined with a lack of physical activity, excess calories take the form of adipose tissue, or fat. Domestic cat obesity is an epidemic with a current prevalence of 45%, meaning almost 1 in 2 domestic cats are obese. Obesity in cats is associated with many health conditions including insulin resistance, urinary diseases, neoplasia, cardiovascular disease and reduced lifespan. These conditions, as well as obesity, are also known to be associated with the gut microbiome in humans. More than 20 studies have investigated the link between obesity and the cat gut microbiome with 16S rRNA gene sequencing but no previous study has investigated this relationship using WGS. Besides allowing more robust taxonomic results than 16S rRNA gene sequencing, WGS also provides a prediction of the community’s functional capacity since all genetic material is sequenced. Ma et al. (2022) used WGS on gut microbiome samples from 8 obese/overweight and 8 normal weight cats. Alpha diversity analyses of the feline gut microbiome illustrated that obese cats harbored less microbial diversity and a lower Firmicutes/Bacteroidetes ratio than lean cats. The decrease in the ratio appeared to be due to decreased Firmicutes relative abundance in obese cats. Interestingly, the Firmicutes/Bacteroidetes ratio shift was the opposite of obese human and mouse models. Functional metagenomic data suggested that obese cats had more copies of fatty acid synthesis-related pathways than lean cats. Altogether, the results indicated a clear divergence between lean and obese cats in taxonomic and functional gut metagenomics. Nonetheless, the findings should be approached with caution, as there are significant differences between the lean and obese cat cohorts. The obese cats included in the study were all neutered males of 6 years of age which were on the LabDiet laboratory feline diet 5003. The lean cats were of ages 4 months to 6 years, reproductively intact, and were fed on Hill’s Science Diet Adult Chicken Recipe Dry Cat Food, with no mention of the sexual demographics of the lean cats. These differences make it unclear whether the taxonomic and functional differences identified are due to obesity itself or to the age and sex demographics of the two cat groups. Further work in this field, with matched age, sex, and diet cohorts, could clarify these results.

Barış Özdinç

Barış Özdinç analyzes microbiome research with his educational background in genetics and evolution. As a research analyst for CosmosID, he combines metagenomics and data analyses to identify microbial biomarkers in disease cohorts and evaluate microbiome research tools. His work involves curating microbiome data and creating interesting microbiome content for newsletters and blog posts. Barış Özdinç received his bachelor’s degree in genetics and master’s degree in biodiversity, evolution, and conservation from University College London (UCL). Currently, he lives in Istanbul, Turkey, where he lives with his cat, Delight, and mentors female students in their STEM career pursuits.

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